In the case of machines, such as robots, machine tools and/or production machines for example, movable elements of the machine, such as tools or workpieces, have to be positioned precisely. To position the element in the case of commercially available machines a positioning command, for example to displace the element to a defined target location, in other words to a defined position, is sent to a reference variable generation unit as an input variable. The reference variable generation unit uses the positioning command to generate a corresponding setpoint position variable, which is forwarded in the form of individual setpoint position values as a setpoint variable to a controller for positioning the element. The controller controls a drive unit of a machine axle, which then displaces the element according to the setpoint position variable and positions it thus. In the case of many machines, for example plastics machines or presses, it is often necessary to limit physical variables that occur during the displacement process, for example the pressure and/or force occurring. A so-called limit controller is generally used for this purpose, which intervenes when a setpoint value (for example maximum permitted pressure and/or force) is exceeded and outputs a limit variable, by which the setpoint position variable generated by the reference variable generation unit is reduced, before the setpoint position variable is forwarded to the controller as the setpoint variable for the controller. Since the controller no longer receives the original setpoint position variable but a thus modified (reduced) setpoint variable as the input variable, precise positioning of the element to be displaced no longer takes place. The element to be displaced is therefore not positioned precisely in the target location defined by the positioning command but the displacement movement of the element is stopped earlier so that the target location is no longer reached.
In such an instance until now an operator of the machine generally had to displace the element by manual control into the required position, in other words to the target location, or the displacement speed of the element had to be reduced, so that for example the force occurring, which occurred during displacement of the element, is smaller and the limit controller no longer intervenes and the setpoint position variable is thus not reduced, before the setpoint position variable is forwarded to the controller as a setpoint variable for the controller. However these procedures used until now result in longer processing times and therefore higher costs.